Slang a dose of a depressant mixed with a stimulant, as heroin or morphine mixed with cocaine or an amphetamine
See speedball in American Heritage Dictionary 4
noun
A game resembling soccer but differing mainly in that a ball caught on the fly may be passed with the hands and points may be scored by a forward pass over the goal line.
Slang An intravenous dose of cocaine mixed with heroin or an amphetamine.